class Container {
    static of (value) {
        return new Container(value)
    }

    constructor(value) {
        this._value = value
    }
    
    map (fn) {
        return Container.of(fn(this._value))
    }
}

class Maybe {
    static of (x) {
        return new Maybe(x)
    }

    isNothing () {
        return this._value === null ||this._value ===undefined
    }

    constructor (x) {
        this._value = x
    }

    map (fn) {
        return this.isNothing()?this:Maybe.of(fn(this._value))
    }
}

module.exports = {Maybe,Container}